Disallow `accesskit` on Android NativeActivity, making `hello_android` working again (#6855)

Follow up for https://github.com/emilk/egui/pull/6766

I wasn't sure if `compile_error` is appropriate. It felt right.

.github/workflows/rust.yml

@@ -176,7 +176,9 @@ jobs:
       - name: Set up cargo cache
         uses: Swatinem/rust-cache@v2
 
-      - run: cargo check --features wgpu,android-native-activity --target aarch64-linux-android
+        # Default features disabled to turn off accesskit, which does not work
+        # with NativeActivity.
+      - run: cargo check --features wgpu,android-native-activity --target aarch64-linux-android --no-default-features
         working-directory: crates/eframe
 
   # ---------------------------------------------------------------------------

crates/eframe/src/lib.rs

@@ -144,6 +144,15 @@
 #![warn(missing_docs)] // let's keep eframe well-documented
 #![allow(clippy::needless_doctest_main)]
 
+// Limitation imposed by `accesskit_winit`:
+// https://github.com/AccessKit/accesskit/tree/accesskit-v0.18.0/platforms/winit#android-activity-compatibility`
+#[cfg(all(
+    target_os = "android",
+    feature = "accesskit",
+    feature = "android-native-activity"
+))]
+compile_error!("`accesskit` feature is only available with `android-game-activity`");
+
 // Re-export all useful libraries:
 pub use {egui, egui::emath, egui::epaint};
 

examples/hello_android/Cargo.toml

@@ -17,7 +17,11 @@ crate-type = ["cdylib", "lib"]
 
 
 [dependencies]
-eframe = { workspace = true, features = ["default", "android-native-activity"] }
+eframe = { workspace = true, default-features = false, features = [
+    "default_fonts",
+    "glow",
+    "android-native-activity",
+] }
 egui_demo_lib = { workspace = true, features = ["chrono"] }
 
 # For image support: